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Unconventional tight oil and gas resources, including shale oil and gas, have become the main focus for increasing reserves and production. The safe and efficient development of unconventional oil and gas is a crucial demand for the energy development strategy. Deep tight oil and gas resource development generally adopts horizontal well drilling methods. During drilling, especially in long horizontal sections, the high temperature frequently causes failures of downhole drilling tools and rotary steering tools. The temperature rises sharply during rock breaking with the drill bit. Existing wellbore heat transfer models do not fully consider the impact of heat generated by the drill bit on the wellbore temperature field. This paper aims to experimentally study the temperature rise law of the cutting tooth of the bottom polycrystalline diamond compact (PDC) bit during rock breaking. A set of evaluation devices was developed to study the temperature field distribution characteristics at the bottom of the PDC bit during rock breaking under different experimental conditions. The results indicate that the flow rate of drilling fluid, bit rotation speed, and weight on bit (WOB) significantly affect the distribution of the temperature field at the well bottom. This experimental research on the temperature field distribution characteristics at the bottom of the PDC bit during rock breaking helps reveal the heat transfer characteristics of the long horizontal section wellbore, guide the optimization of drilling parameters, and develop temperature control methods. It is of great significance for the advancement of efficient development technologies for unconventional resources in long horizontal wells. [ABSTRACT FROM AUTHOR]

The atomization of sewage sludge is a key step in its drying process. This study conducts an industrial-scale experimental study to investigate the performance of a self-developed internal-mixing air-blast nozzle for atomizing sewage sludge. The size of atomized droplets is calculated using image processing technology. Using the specific size and characteristic size of the droplets, the droplet distribution and the droplet motion behavior in spray field are investigated at various air-to-liquid mass flow rate ratio (ALR). The larger the ALR, the smaller the atomization droplets. By installing outlet diffusers and impaction pins, the atomization angle can be increased and the distribution of droplets in the spray field can be improved. The outlet diffuser with an outlet angle of 90° and the square impaction pin exhibit optimal effect. Experiments with real scale and industrial grade have a significant reference value for industrial applications of sludge atomization. [ABSTRACT FROM AUTHOR]

In order to verify the impact of transceiver hardware impairments on the performance of communication system, we explore the robust transmission design of an intelligent reflecting surface (IRS) aided simultaneous wireless information and power transfer (SWIPT) communication system in consideration of hardware impairments of transceiver. Under the constraints of maximum transmitting power of base station, the minimum receiving energy of the energy collector and IRS passive beamforming, the optimization objective is set to maximize the weighted sum rate of all information receivers. And the block coordinate descent (BCD) algorithm is used to decompose the optimization problem into multiple optimization subproblems for alternate optimization. The Lagrange dual method and maximization minimization (MM) algorithm are respectively adopted to solve the optimization problems of active beamforming and IRS passive beamforming. Simulation results validate the impact of transceiver hardware impairments on system performance, and also confirm that the hardware impairment at information receiver is more obvious than the hardware impairment at base station transmitter. [ABSTRACT FROM AUTHOR]